Error: Missing JavaFX application class TextEditor with RichTextFX

Question

This is the image error!

I checked out many sources on how to fix this problem! I am using Java 15, and I have the RichTextFX jar file version 0.10.6 installed. I am getting this error but I do not know why, as according to documentations I am doing everything correctly. JavaFX also works fine for me, I have javafx 16 installed. This is my code:

CodeArea codeArea = new CodeArea();
@Override
public void start(Stage stage) throws Exception {
    // TODO Auto-generated method stub
    
    MenuBar menuBar = new MenuBar();
    Menu menu1 = new Menu("File");
    Menu menu2 = new Menu("Edit");
    Menu menu3 = new Menu("Project");
    Menu menu4 = new Menu("Window");
    Menu menu5 = new Menu("Help");
    
    menuBar.getMenus().add(menu1);
    menuBar.getMenus().add(menu2);
    menuBar.getMenus().add(menu3);
    menuBar.getMenus().add(menu4);
    menuBar.getMenus().add(menu5);
    
    BorderPane borderPane = new BorderPane();
    HBox statusbar = new HBox();
    TabPane tabPane = new TabPane();
    
    
    codeArea.setParagraphGraphicFactory(LineNumberFactory.get(codeArea));
    
    Tab tab1 = new Tab("Untitled", codeArea);
    tabPane.getTabs().add(tab1);
    borderPane.setTop(menuBar);
    borderPane.setCenter(tabPane);
    borderPane.setBottom(statusbar);
    
    Scene scene = new Scene(borderPane);
    stage.setScene(scene);
    stage.setMaximized(true);
    stage.setTitle("Gooye");
    stage.show();
    
    
}